Playlists provide a mechanism for users to organize media items for playback on a computing device. A user can generate a personal playlist that incorporates songs from the user's digital music library, for example. Users can share playlists. For example, a user can subscribe to a playlist created or curated by another user and receive information describing the curator's playlist. When the curator of a playlist updates the playlist, subscribers to the playlists can receive data that describes the updates to the subscribed playlist.